This proposal is to establish a Specialized Center of Research in Hemostatic and Thrombotic Diseases in the Texas Medical Center, based at the Baylor College of Medicine, Houston. The proposal focuses on the process of arterial thrombosis, beginning with the initial step of platelet adhesion mediated by the platelet glycoprotein (GP) Ib-IX-V complex and subendothelial von Willebrand factor (vWF), and culminating in the formation of a fibrin cross-linked thrombus that may completely occlude a blood vessel and cause tissue infarction. In addition to examining basic mechanisms of thrombus formation, we will investigate two clinical disorders, one a consequence of thrombosis, the thrombotic microangiopathies, and one complicated by thrombosis, peripheral arterial disease.